Conventionally, a ceramic based composite material (i.e., a composite material) is known that is formed by adhering a matrix phase that is formed from silicon carbide onto a fiber fabric that is formed from silicon carbide. This type of ceramic based composite material (referred to below as SiC/SiC) is lightweight and has a high level of thermostability that is used as a formative material for rocket injection nozzles and the like. As is disclosed in Japanese Unexamined Patent Application, First Publication No. 2000-219576, the matrix phase in this SiC/SiC is formed by performing a combination of chemical vapor infiltration (CVI) and polymer infiltration and pyrolysis (PIP) on the surface of the heated fiber fabric.